Descriptive Statistical Analysis Report on the Results of Questionnaire and Observations on Patients With Physiological Halitosis Who Visited the KUMC Halitosis Clinic- A Retrospective Study

Background: We initiated to prepare the basic data that could help us to understand the characteristics of patients with physiological halitosis symptoms in Korea and aid in explaining the causes of these symptoms. Methods: We collected questionnaire and dietary analysis results from the data of 246 adult patients diagnosed with physiological halitosis symptoms, collected the data from the patients’ salivary measurements and the analysis data of patients’ tongue and throat management status. Using the SPSS (IBM SPSS™, Ver. 22.0) program, we performed a frequency analysis, calculating the correlation coecient Phi with an independence test. Results: The mean age and one standard deviation of 246 patients with physiological halitosis was 41.85±11.63 years. The proportion of women, the proportion of patients who replaced breakfast with fast food or skipped breakfast, with beverage drinking habits such as coffee, tea, or carbonated drink, with irregular or insucient consumption of water, who recognized their own oral malodor, suffering anxiety or stress over oral malodor, with an introverted personality, with insucient unstimulated salivation volume, with incorrect tongue management, and with PND (Postnasal drip) or PTC (Posterior Tongue Coating) were all statistically analyzed to be signicant (p < 0.05). As a result of the correlation analysis, the Phi values of the seven pairs of the bivariate variables were from 0.137 to 0.196, and the Phi values of the ve pairs of the bivariate variables - the Phi value between the breakfast pattern variable and the regular diet variable, the Phi value between the stimulating menu variable and the drinking variable, the Phi value between the unstimulated saliva variable and the stimulated saliva variable, the Phi value between the unstimulated saliva variable and the sedimentation ratio of saliva variable, and the Phi value between the stimulated saliva variable and the sedimentation ratio of saliva variable - were from 0.203 to 0.394 (p < 0.05). Conclusion: We could suggest the 10 potential common risk factors related to physiological halitosis symptom, and the ve pairs of variables with Phi values ranging from 0.20 to 0.40 could be judged to have a moderate correlation.

between the unstimulated saliva variable and the stimulated saliva variable, the Phi value between the unstimulated saliva variable and the sedimentation ratio of saliva variable, and the Phi value between the stimulated saliva variable and the sedimentation ratio of saliva variable -were from 0.203 to 0.394 (p < 0.05).
Conclusion: We could suggest the 10 potential common risk factors related to physiological halitosis symptom, and the ve pairs of variables with Phi values ranging from 0.20 to 0.40 could be judged to have a moderate correlation.

Background
Oral malodor refers to exhaled breath that a person or a third party nds to be unpleasant. Oral malodor patient is a patient who has anxiety about oral malodor caused by physiological, physical and mental causes [1]. In the past, depending upon the person perceiving themselves as having oral malodor, this problem could be classi ed as either self-reported halitosis (subjective halitosis) or objective halitosis, as recognized by other people. These more usually have been classi ed as genuine halitosis, pseudo halitosis, and halitophobia. In the past, many scholars had adopted this classi cation around the world [2]. But instead, the authors of the present study have adopted the classi cation of physiological and pathological halitosis as proposed by the Japanese Academy of Malodor Syndrome (JAMS) and the Korean Academy of Halitosis Control under the Korean Academy of Preventive Dentistry and Oral Health (KAPDOH) [3]. Accordingly, we can classify pathological halitosis as being oral malodors resulting from diseases of the oral region, the otorhinolaryngological system, neurological disorders, mental disorders, or from systemic medical diseases. We can also classify physiological halitosis as oral malodor occurring when a person wakes up in the morning, gets hungry, becomes tense, is tired, during a woman's menstrual uctuations, when pregnant or in puberty, during menopause, or after the ingestion of favorite foods, ordinary foods, or certain drugs [1,3].
Looking at the trend of recent published papers related to halitosis, Bigler and Filippi conducted a survey on the perception of oral malodor among adolescents and young people [4], and Jongh et al. analyzed the effect of oral malodor on social activities [5]. They reported on the social discomfort caused by oral  [20], and Patel et al. argued that social anxiety, poor oral hygiene, and coated tongue were associated with subjective halitosis [21].
But the above scholars did not comprehensively explain the causes and treatment methods for physiological halitosis [22]. Therefore, we performed a descriptive statistical analysis of a questionnaire to determine patients' dietary habits, their own perceptions of oral malodor, and lifestyle habits that could induce oral malodor. We also analyzed the results of salivary measurements and photographic data of the tongue and throat of 246 patients with physiological halitosis symptoms who had visited the KUMC (Korea University Medical Center) Oral Malodor Clinic from 2009 to 2020. We then were able to prepare the basic data that could help us to understand the characteristics of patients with physiological halitosis symptoms in Korea and also aid in explaining the causes of these symptoms.

Study participants
The study population consisted of 246 adult patients diagnosed with physiological halitosis symptoms, excluding minors under the age of 18, who had visited the KUMC Halitosis Clinic from 2009 to 2020. All data was obtained from the patients' surveys and examination records at the time of physiological halitosis diagnosis, but we excluded the patients' name, dental diagnosis & treatment record number, resident registration number, and contact information.

Data collection from questionnaires and dietary records
From the contents of questionnaires and dietary records, we collected the patients' data including age, sex, breakfast patterns, three-meal-a-day dietary habits, soft drink beverage habits, snack consumption patterns, stimulating menu choices, daily water intake frequency, oral malodor self-awareness or selfconsciousness, anxiety or stress over halitosis, toothbrushing frequency, mouth breathing or smoking habits, drinking patterns, and their character, using the data collection form shown in Table 1. We also collected the data from the patients' salivary measurements and the analysis data of the patients' tongue and throat photographs obtained by use of an intraoral camera (Spirit II™, Dentall, Korea), as being the amount of unstimulated saliva, the amount of stimulated saliva, the sedimentation ratio of saliva, the patients' tongue care status such as red tongue or coated tongue or healthy tongue, and whether they had PND (postnasal drip) or PTC (posterior tongue coating), using the data collection form shown in Table 1.

Statistical analysis
Using the SPSS (IBM SPSS™, Ver. 22.0) program, we performed a frequency analysis for each of 19 variables in data collected from 246 physiological halitosis patients. For the statistically signi cant (p < 0.05) variables among these, we calculated the correlation coe cient Phi with an independence test and investigated the correlation among the variables. All p-values were two-sided and if below 0.05 the results were considered statistically signi cant.

Ethical approval
This research protocol was approved by the Institutional Review Board of Korea University Guro Hospital.

Results
Using the standards in Table 1, we obtained descriptive statistical analysis results of the 246 patients, who had been diagnosed with physiological halitosis, as summarized in Table 2 and Table 3. In addition, for the 17 bivariate variables that were statistically signi cant (p < 0.05) as shown in Table 3, we performed an independence test. We could then summarize the statistically signi cant (p < 0.05) correlation results of 12 combinations as shown in Table 4. The mean age and one standard deviation of 246 patients with physiological halitosis was 41.85±11.63 years, and the proportion of women was statistically signi cantly high (p=0.022). We analyzed the proportion of patients who replaced breakfast with fast food or skipped breakfast (p<0.001), the proportion of patients with beverage drinking habits such as coffee, tea, or carbonated drink (p<0.001), the proportion of patients with irregular or insu cient consumption of water (p<0.001), the proportion of patients who recognized their own oral malodor (p<0.001), the proportion of patients suffering anxiety or stress over oral malodor (p<0.001), and the proportion of patients with an introverted personality (p<0.001) to be statistically signi cantly high. And the proportion of the patients with insu cient unstimulated salivation volume (less than 3.0mL / 3.0 min) (p<0.001), the proportion of the patients with incorrect tongue management (p<0.001), and the proportion of patients with PND in the throat or PTC on the posterior surface of tongue (p<0.001) were all statistically analyzed to be signi cantly high.

Discussion
Many preceding research results show that the correlation between the measurement values by use of halitosis measuring devices such as Halimeter™ or Oral Chroma™ and the organoleptic test (OLT) results is high [4,23], although F. Brunner et al. argued that the organoleptic test would be a gold standard that could be used to diagnose halitosis so far [23]. Based on these arguments, we performed an organoleptic test in the KUMC Halitosis Clinic, measuring the perceivable distance of oral malodor with the patient's own mouth open, measuring the perceivable distance of exhaled oral malodor, based on the standards suggested by Seemann et al. [17,24]. Among those who were complaining of physiological halitosis symptoms, we judged the patient with perceivable oral malodor at a distance of 10 cm or more from the patient's lips (which is more than grade 1 by Seemann et al. [24]) as having physiological halitosis. At the same time as the organoleptic test, we measured the oral malodor of the 246 physiological halitosis patients with oral malodor measurement devices such as mBA-21 (TAIYO, Japan), Twin-Breasor II (iSenLab, Korea), and mBA-400(TAIYO, Japan), all approved by the Ministry of Food and Drug Safety in Korea. But the measurement results of these three types of devices did not show consistent correlations with the organoleptic test results, as Halimeter™ and Oral Chroma™ used in previous studies [3,4,23].
Therefore, in this study process we excluded those measurement results from our analysis. Because the gas output patterns of patients with physiological halitosis symptoms might differ from patient to patient, and because the three types of oral malodor measuring devices would each have their own characteristic measuring spectrum, we thought a separate research report on this topic should be made in near future.
And as shown in Table 3 and Fig 1, patients who replaced with fast food or skipped breakfast were analyzed to be more than those who used to have breakfast of ordinary Korean menu, then it was inferred that the breakfast pattern could cause symptoms and it was also interpreted to uphold the assertion of A Wälti et al., who claimed to consume foods high in ber for breakfast in order to reduce the occurrence of oral malodor [17]. Whereas patients who had preferred coffee, tea, or carbonated beverages were found to be more numerous than those who seldom drank those beverages, we concluded that patient preference for these beverages could affect the occurrence of physiological halitosis symptoms. There were more patients who drank insu cient amounts of water during a day as compared to those who regularly drank su cient amounts of water. Thus we concluded that the amount of water drunk daily could affect the occurrence of physiological halitosis. Among patients with physiological halitosis symptoms, 89.0% of them were aware of their own halitosis, and 97.6% of those had anxiety or stress because of oral malodor. It was found that by recognizing their own halitosis, they were worrying about this condition and progressed through to physiological halitosis symptoms. This was in accord with the results of reports from Wang and He, Troger B et al., and M. Fukui et al., who insisted that in many halitosis patients, anxiety, stress and worry could be found [8,15,20]. In the evaluation of the patient's own personality, a statistically signi cant number of responding patients said that their own personality was introspective. Therefore, it was thought that people with tendencies towards introversion were likely to be exposed to the risk of physiological halitosis symptoms as compared to people with a tendency to extraversion.
As shown in Table 3 and Fig 1, the frequencies of several factors that were expected to cause physiological halitosis symptom were statistically analyzed to be signi cantly high in the proportion of patients with a healthy lifestyle (p < 0.05). Thus, we inferred that the patients' failure to adhere to a threemeal-a-day habit, their preference for a stimulating diet, a toothbrushing frequency of at least four times a day, their smoking or mouth breathing habits, or a drinking frequency at least twice a week might only be a problem in a small number of the patients suffering physiological halitosis symptoms. In addition, there was no statistical difference in patient snack preference that could remain in the oral cavity for a long time, which had been suspected as a predisposition to physiological halitosis symptom. Thus we concluded that a questionnaire related to this factor could be omitted if such would be developed later for investigating Korean physiological halitosis patients.
When we measured the amount of salivation, we adopted one of the standards (the adopted standard: 3.0mL / 3.0min) suggested by the JAMS [3] and the Korean Academy of Halitosis Control under the KAPDOH [1]. As for the domestic research related to the amount of salivation in Korean people, Kim et al. suggested that the unstimulated salivation amount was 0.66 ± 0.41g/min and the stimulated salivation amount was 1.61 ± 0.69g/min [25]. Most other domestic researchers had only suggested a range of salivation amount according to age groups. So, we inferred that research aimed at suggesting a standardized amount of salivation for men and women in Korea was needed. In this study, in the case of the unstimulated saliva, 78.5% of patients showed lower measurement values than the baseline measurement value (3.0mL / 3.0min), and this result was also consistent with the report of N. Suzuki et al., who insisted that there was a decrease of unstimulated salivation amounts in the halitosis patients [12]. In the case of stimulated salivation amounts, some su cient amount of saliva was measured, so 87.0% of the patients exceeded the reference value that the JAMS had suggested [3] and that the KAPDOH had approved [1] (p < 0.05). Only in a few cases was it con rmed that the level of the stimulated salivation amount was less than the suggested value. Therefore, it could be inferred that if there were no properly applied stimulations for salivary secretion, most patients with physiological halitosis symptoms could not utilize their properly produced saliva. This would then cause dryness in the oral cavity, resulting in oral malodor. On the other hand, the patients with a salivary sedimentation ratio of less than 10%, also determined by the standard suggested and approved by the JAMS and the KAPDOH [1,3], were statistically signi cantly greater than the number of patients with a salivary sedimentation ratio of 10% or more. But in about 43.5% of the physiological halitosis symptom patients, we could measure salivary sedimentation ratios of 10% or greater. So we could not help reasoning the relationship between the salivary sedimentation ratio and the physiological halitosis symptom. M. Ueno et al. argued that salivary turbidity was associated with halitosis [18]. Thus we inferred that in our study, the degree of salivary turbidity and of salivary contamination of patients with a salivary sedimentation ratio of 10% or more was highly correlated with the occurrences of physiological halitosis.
As a result of the analysis of patient tongue records, cases of patient red tongue or coated tongue caused by excessively wiping off or the accumulation of tongue coating, occurred in 91.5% of the patients. We concluded that incorrect management of the patient's own tongue could be closely related to physiological halitosis. This conclusion is in accord with the results of studies by previous scholars [9,12,21], so we suggest patient education on correct tongue management. As a result of our analysis of intraoral photographs, we found postnasal drip in the throat and posterior tongue coating in 92.3% of the patients with physiological halitosis, and it could be expected that postnasal drip and posterior tongue coating would increase the viscosity of the patient's saliva. Based on the argument of M. Ueno et al., who stated that high saliva viscosity could increase the possibility of physiological halitosis [19], we thought that postnasal drip in the throat and posterior tongue coating could be also one cause of physiological halitosis. It would then be desirable to add an intraoral photograph of the postnasal drip in the patient's throat and the posterior tongue coating to aid in diagnosing physiological halitosis.
By synthesizing the results of the frequency analysis as described above, we identi ed the 10 variables as being "the sex" variable, "the breakfast pattern" variable, "the soft drink" variable, "the water intake" variable, "the self-awareness" variable, "the anxiety or stress for one's own halitosis" variable, "the character" variable, "the unstimulated saliva" variable, "the red tongue or coated tongue" variable, and "the postnasal drip or posterior tongue coating" variable. We set these variables as being the potential common risk factors related to physiological halitosis. Then, when examining or consulting patients with physiological halitosis, we concluded that it would be necessary to investigate these 10 factors in our investigation.
On the other hand, as shown in the results of the correlation analysis between the bivariate variables in

Conclusion
The authors could identify 10 variables as being sex, breakfast pattern, soft drink, water intake, selfawareness, anxiety or stress for one's own halitosis, character, unstimulated saliva, red tongue or coated tongue, and postnasal drip or posterior tongue coating, and we suggest that these are the potential common risk factors related to physiological halitosis. And the Phi values between the breakfast pattern variable and the regular diet variable, between the stimulating menu variable and the drinking variable, between the unstimulated saliva variable and the stimulated saliva variable, between the unstimulated saliva variable and the sedimentation ratio of saliva variable, and between the stimulated saliva variable and the sedimentation ratio of saliva variable could be judged to have a moderate correlation. Therefore, in a future study on physiological halitosis, we would suggest that a comprehensive study on the possibility of physiological halitosis symptom outbreaks caused by these potential common risk factors and the interactions of these moderately correlated factors would be necessary. Availability of data and materials The data that support the ndings of this study are available from Korea University Guro Hospital, but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Data are however available from the authors upon reasonable request and with permission of Korea University Guro Hospital.

Competing interests
The authors declare that they have no competing interests.

Funding
The research did not receive any speci c grant from funding agencies in the public, commercial, or not-for pro t sectors.
Authors' contributions Y Kim's role on this research were conceptualization, design of the work, data curation, formal analysis, interpretation of data, project administration, supervision, visualization, and writing-original draft, and D Ma's role on this research were investigation, validation, writing-review and editing. All authors read and approved the nal manuscript.